Heritabilities and Correlations of Growth and Carcass Traits of Hereford Steers

The efficient production of desirable carcasses is the ultimate objective of present beef cattle breeding programs. The traits which contribute to efficiency of production are: (1) growth rate and (2) efficiency of feed utilization. These two traits are of economical importance to producers of beef cattle. Carcass quality and quantity of edible meat, as determined by U.S.D.A. carcass grades, and carcass weight are the determining factors for dollars returned to the producer of beef. Carcass composition (percent fat, lean and bone) is directly related to carcass grades and gross return. Therefore, muscling of the live animal as it influences carcass composition is important in beef production. A knowledge of the heritability of these traits and relationships among them is needed to guide selection procedures for efficient beef production. The objectives of this study were: (1) calculate heritability estimates of growth and carcass characteristics in beef cattle, (2) determine correlations among growth and carcass characteristics. The data used in this study were collected at the Fort Robinson Beef Cattle Research Station, Crawford, Nebraska and the University of Nebraska Agricultural Experiment Station, Lincoln. One hundred twenty-eight Hereford steers produced at Fort Robinson from a herd of grade Hereford cows bred to bulls produced in various experimental breeding herds were the source of data used in this study. There were 31 steers, representing 19 sire groups, born in 1956 and 97 steers, representing 20 sire groups, born in 1957. Growth and carcass data on one hundred and twenty- eight Hereford steers produced at Fort Robinson and fattened at Lincoln were studied. Estimates of heritability and phenotypic correlations were computed among several measures of growth rate and carcass traits. Advisor: Robert M. Koc